The thermal characteristics and the mitigation potential of a medium size urban park in Athens, Greece

An urban park located in a densely built area of  Western Athens, Greece is monitored. Temperature data from 15 urban and suburban stations are also used to perform comparative analysis at the city level. The park presents an important temperature inhomogeneity during day and night due to the variable radiative cooling capacity and shading potential between its various zones. Average nocturnal Cool Island Intensities (CII) against the reference urban stations varied between – 0.7 K to – 2.8 K while during the daytime the maximum CII was between -0.2 to -2.6 K. A statistical significant correlation between the magnitude of the CII and the population density index is found for both day and night. The data analysis showed that the park was warmer than the urban stations for ambient temperatures lower than 34 °C, while for higher urban temperatures the park remained cooler. Moreover the absolute CII increased as a function of the ambient temperature. A strong correlation with the wind speed is observed for speeds higher than 6 m/sec. The mitigation potential of the park was assessed by using three traverses in and around the park. The analysis of the Park Cooling Index (PCI) showed a variation from 3.3 to 3.8 K. The traverses' temperature gradient was estimated to be between 0.16 to 1.4/100m.The climatic influence of the park was extended up to 300 m away from the borders of the park.